Compression spring assembly and methods of using the same

ABSTRACT

An all plastic compression spring assembly includes a slotted tubular spring element formed from a tensile polymer material and upper and lower loading cones received at opposing upper and lower ends of the slotted tubular spring element. The upper loading cone may be axially compressible towards the lower loading cone within the slotted tubular spring element whereby the slotted tubular spring element radially expands in tension to create an opposing radial contraction force, and in turn, an axial extension spring force. When released, the spring element elastically returns to its normal at rest shape, returning the cones to their normal at rest positions. In some dispenser configurations, the lower loading cone may be stationary or fixed within the dispensing head and the upper loading cone may be downwardly compressible toward the lower loading cone by movement of a nozzle head.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/861,056, filed Jan. 3, 2018.

BACKGROUND OF THE INVENTION (1) Field of the Invention

The instant invention generally relates to compression spring systemsand more particularly to a compression spring assembly including apolymer spring element for use in a dispensing pump.

(2) Description of Related Art

Dispensing pumps for various liquids, lotions, gels, etc. are known inthe art. They generally comprise a body portion which is seated on theneck of a container, a co-acting nozzle portion which slides relative tothe body portion, and a spring structure which biases the co-actingnozzle portion to its normal rest position. To dispense the material inthe container, the user manually depresses the nozzle which forces thematerial from the inside of the body portion outwardly through thenozzle. When the nozzle is released, the spring forces the nozzleportion back to its normal resting position. Most of the pump systemcomponents are typically formed from polymer materials, with theexception of the spring, which is typically formed from metal. Theplastic components are easily recyclable. However, the presence of themetal spring in the pump assemblies has been found to impede or slow therecycling process due to the need to separate the metal spring from theother plastic components. Accordingly, there is a need in the industryfor all plastic spring systems for use in various devices such asdispensing pumps.

SUMMARY OF THE INVENTION

An exemplary embodiment of a compression spring assembly according tothe present invention includes a slotted tubular spring element formedfrom a tensile polymer material, and first and second loading conesreceived at opposing first and second ends of the slotted tubular springelement. In some embodiments, both the spring element and the loadingcones may be formed from polymer materials, making the spring assemblymore easily recyclable.

In the exemplary embodiment, the slotted tubular spring element iscylindrical in shape and has a uniform wall thickness. The loading conesare generally conical in shape and preferably have at least one wallsection with a wall angle of no less than 11 degrees. Wall angles ofless than 11 degrees tend to create a friction lock while wall angles ofgreater than 11 degrees minimize stroke length and increase overallspring assembly diameter. The exemplary embodiment includes loadingcones with a first frustoconical pre-loading wall section having a wallangle of greater than 11 degrees, and a second frustoconical primaryloading wall section having a wall angle of 11 degrees.

The loading cones are axially compressible toward each other within theopen ends of the slotted tubular spring element whereby the slottedtubular spring element radially expands in tension to create an opposingradial contraction force. Deformation of the tubular spring wallselastically stores energy which will return the spring to its normal atrest shape when released. When released, the spring element elasticallycontracts, in turn creating an axial extension force, and returns thecones to their normal at rest positions.

Some embodiments of the spring assembly include a modified springelement having strain reducing ribs extending along the opposing edgesof the longitudinal slot. The ribs may include outwardly convex surfacesextending both radially outward and circumferentially outward from theslot edges. This embodiment further includes a first thinner wallthickness at the slot edges and a second thicker wall thicknessdiametrically opposed from the slot edges. The arcuate surface alongwith the increasing wall thickness moving away from the slot edges, moreevenly distributes strain throughout the spring element and extends thelife cycle of the spring element.

Other embodiments of the spring assembly include a spring element whichis hyperboloid in shape.

Embodiments of the present polymer compression spring may beadvantageously used in dispensing pumps for various liquids, lotions,etc. In some exemplary embodiments, all of the components of both thedispenser pump and the compression spring assembly are molded from thesame plastic material making the entire dispensing pump easilyrecyclable in a single plastic material classification. Exemplaryplastic materials include polypropylene (PP), high-density polyethylene(HDPE), and low-density polyethylene (LDPE). However, the disclosureshould not be considered to be limited to these materials.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming particular embodiments of the instant invention,various embodiments of the invention can be more readily understood andappreciated from the following descriptions of various embodiments ofthe invention when read in conjunction with the accompanying drawings inwhich:

FIG. 1 is a plan view of an exemplary compression spring assembly inaccordance with the present invention;

FIG. 2 is a perspective view of the slotted tubular spring element in anat rest condition;

FIG. 3 is a perspective view of the slotted tubular spring element in aradially expanded condition;

FIG. 4 is a top view of the spring element;

FIG. 5 is a front view thereof;

FIG. 6 is a side view thereof;

FIG. 7 is a cross-section view thereof taken along line 7-7 of FIG. 4;

FIG. 8 is an enlarged plan view of the loading cone;

FIGS. 9-12 are sequential views of the compression spring assembly beingaxially loaded and released;

FIG. 13 is a cross-sectional view of an exemplary dispensing pumpincorporating the present compression spring assembly;

FIG. 14 is a front view of another exemplary embodiment of the slottedtubular spring element including strain reducing ribs;

FIG. 15 is a top view thereof;

FIG. 16 is a side view thereof;

FIG. 17 is a perspective view thereof in a radially expanded condition;

FIGS. 18 and 19 are side and front views thereof showing the bendingvectors of the ribs when the spring element is expanded;

FIG. 20 is an illustration showing initial axial compression of thespring assembly;

FIG. 21 is another illustration showing full axial compression of thespring assembly;

FIG. 22 is a plan view of another exemplary compression spring assemblyincluding a hyperboloid spring element;

FIG. 23 is a perspective view of the hyperboloid slotted spring element;

FIG. 24 is a front view thereof;

FIG. 25 is a top view thereof;

FIG. 26 is a cross-sectional view thereof taken along line 26-26 of FIG.25; and

FIG. 27 is a perspective view of another exemplary dispensing pumpincorporating the hyperboloid compression spring assembly.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, an exemplary embodiment of the presentcompression spring assembly is generally indicated at 10 in FIG. 1-12.According to the present invention, the compression spring assembly 10comprises a slotted tubular spring element 12 formed from a tensilepolymer material, and first and second loading cones 14, 16 received atopposing first and second ends of the slotted tubular spring element 12.In some embodiments, the loading cones 14, 16 could be formed fromnon-plastic materials, depending on the implementation. However, in thepreferred embodiments as disclosed herein, both the spring element 12and the loading cones 14, 16 are formed from polymer materials.Exemplary plastic materials include polypropylene (PP), high-densitypolyethylene (HDPE), and low-density polyethylene (LDPE). However, thedisclosure should not be considered to be limited to these materials. Inparticular, the various components may be molded from HDPE and/or LDPE,making the entire spring assembly more easily recyclable.

In the exemplary embodiment, the slotted tubular spring element 12 iscylindrical in shape and has a uniform wall thickness (best illustratedin FIGS. 2 and 4). The spring element 12 includes a single longitudinalslot 18 which extends the entire length of the tube to define parallelopposing slot edges 20, 22. The slot 18 allows the element 12 to expandradially upon the application of an axial force at the first and secondends thereof. The inner wall edges are chamfered 24 to facilitatesliding of the walls over the loading cone surfaces 14. 16 (bestillustrated in FIG. 7).

The loading cones 14, 16 are identical in shape and are symmetricallyinverted to provide opposing axial compression and extension forces onthe tubular spring element 12. Referring to FIG. 8, the loading cones14, 16 (only 14 is shown) are generally conical in shape and preferablyhave at least one wall section (primary loading wall) 26 with a wallangle θ¹ of no less than 11 degrees. In the present embodiment, a wallangle of less than 11 degrees tends to create a friction lock while awall angle of greater than 11 degrees minimizes stroke length andincreases overall spring assembly diameter. It should be understood thatthe critical wall angle for the primary loading wall 26 is based on thetype of material used, i.e. polymer or metal, and other factors such assurface finish, shape of wall chamfers, etc. The angle must be selectedsuch that the spring force from the spring element 12 overcomes frictionas well as displacement of the applied axial load. The exemplaryembodiment, which has an intended use in dispensing pumps for viscousliquids, includes loading cones 14, 16 with a first frustoconicalpre-loading wall section 28 having a wall angle θ² of greater than 11degrees, and a second frustoconical primary loading wall section 26having a wall angle θ¹ of 11 degrees. The steeper pre-load angle θ²facilitates the initial expansion of the spring element 12.

Turning to FIGS. 9-12, the loading cones 14, 16 are axially compressibletoward each other within the open ends of the slotted tubular springelement 12 whereby the slotted tubular spring element 12 radiallyexpands in tension to create an opposing radial contraction force. FIG.9 illustrates an initial at rest state. FIG. 10 illustrates initialpre-load and outward expansion of the spring element. FIG. 11illustrates full axial compression and load. Deformation of the tubularspring element 12 elastically stores energy which will return the springelement 12 to its normal at rest shape when released. When released asillustrated in FIG. 12, the spring element 12 elastically contracts(inward), in turn creating an axial extension force, and returns thecones 14, 16 to their normal at rest positions.

Turning to FIG. 13, embodiments of the present polymer compressionspring 10 may be advantageously used in dispensing pumps 100 for variousliquids, lotions, etc. contained within a bottle or other container (notillustrated). In some exemplary embodiments, all of the components ofboth the dispenser pump 100 and the compression spring assembly 10 aremolded from the same plastic material making the entire dispensing pump100 including the spring assembly 10 easily recyclable in a singleplastic material classification.

The dispensing pump 100 comprises an accumulator cup 102 having a cliptube receptacle 104 and ball valve 106 at a lower end thereof. A tubularguide 108 is received in the upper end of the accumulator cup 102, andthe tubular guide 108 is secured on a container neck (not shown) with athreaded cap ring 110. The present compression spring assembly 10 isreceived and guided within the tubular guide 108. As noted above, theangle θ¹ of the loading wall 26 of the loading cones 14, 16 is acritical factor in determining overall spring assembly diameter. As seenin this pump embodiment 100, the spring assembly 10 fits within theinner walls of the guide 108 which in turn must fit within the neck ofthe container. Accordingly, the wall angle, spring element material andprofile are all factors in determining this specification. A piston rod112 is received axially through the loading cones 14, 16 and the tubularspring element 12 and extends through the bottom of the guide 108 intothe accumulator cup 102 wherein the terminal end is fitted with a piston112 which forms a seal with the inner wall of the accumulator 102. Anozzle head 116 is secured to the upper end of the piston rod 112 andreceived over the upper loading cone 16.

In operation, a forcible downward compression of the nozzle head 116causes a corresponding downward axial movement of the upper loading cone16 relative to the lower loading cone 14 and outward deflection andloading of the spring element 12 as per the illustrations earlierdescribed in FIGS. 9-12. Upon the subsequent release of the nozzle head116, the tubular spring element 12 elastically contracts back to itsnormal at rest shape and position (see also FIG. 12), causing a forcibleupward movement of the upper loading cone 16, piston rod 112, piston 114and nozzle head 116 back to their normal at rest positions. The pumpassembly 100 and ball valve 106 operate as known in the art to drawmaterial up from the clip tube 104 and dispense the material through thenozzle head 116.

Turning now to FIGS. 14-21, some embodiments of the spring assembly 200may include a modified slotted tubular spring element 202 having strainreducing ribs 204, 206 extending along the opposing edges 208, 210 ofthe longitudinal slot 212. The ribs 204,206 may include symmetricalconvex surfaces extending both radially outward 204 a, 206 a (See FIGS.15 and 16) and circumferentially outward 204 b, 206 b (See FIG. 14) fromthe slot edges 208, 210. This embodiment 202 further includes a firstthinner wall thickness 214 at the slot edges 208, 210 adjacent thestrain ribs 204, 206 and a second thicker wall thickness 216diametrically opposed from the slot edges 208, 201 (See FIG. 15). Thearcuate surfaces 204 a, 204 b, 206 a, 206 b along with the increasingwall thickness moving away from the slot edges 208, 210 more evenlydistributes strain throughout the entire spring element 202 and extendsthe life cycle of the spring element 202. FIG. 17 illustrates the springelement 202 in an expanded loaded state. FIGS. 18 and 19 illustrate themovement vectors (arrows) associated with the corners of the slot edges208, 210. The reduced material volume in these areas allow these cornersto more easily deform and reduce strain. The present spring element 202is used in combination with the same loading cones 14, 16 as previouslydescribed. FIGS. 20 and 21 show axial compression of the presentembodiment 200 with exemplary loading cones 14, 16. The present springassembly 200 can be used in the same types of dispensing pumps 100 asdescribed above with improved spring longevity.

Referring now to FIGS. 22-27, other embodiments of the compressionspring assembly 300 include a slotted tubular spring element 302 whichis hyperboloid in shape, i.e. having a smaller (narrower) diameter atthe center and symmetrically larger diameters at the ends, and first andsecond opposed loading cones 304, 306. The spring element 302 has auniform wall thickness (See FIGS. 25 and 26) and includes a singlelongitudinal slot 308 (FIGS. 23 and 24) which extends the entire lengthof the tube, allowing the spring element 302 to expand radially upon theapplication of an axial force at the first and second ends thereof. Thecurved spring wall of the hyperboloid spring 302 is provides a stifferloading profile (higher loading profile) using the same amount ofplastic material as compared with the earlier described cylindricalshape (FIGS. 1-12). The inner wall edges are also chamfered 310 tofacilitate sliding of the spring element 302 over the loading cone wallsurfaces 304, 306 (See FIG. 26). The hyperboloid shape of the springelement 302 works more efficiently with loading cones 304, 306 having asingle frustoconical loading wall 312 with a somewhat steeper wall angleθ³ (FIG. 22). The preferred embodiment as illustrated shows a wall angleθ³ of greater than 11 degrees. As noted above, the particular wall angleθ is selected based on the tensile characteristics of the spring element302 as well as material and surface finishes. The exemplary embodimentsare intended to be illustrative but not limiting.

Turning to FIG. 27, the present hyperboloid compression spring assembly300 lends itself to be advantageously used as an exterior spring returnin certain dispensing pumps 400 for various liquids, lotions, etc. Asdescribed above, in many exemplary embodiments, all of the components ofboth the dispenser pump 400 and the compression spring assembly 300 aremolded from the same plastic material making the entire dispensingassembly easily recyclable in a single plastic material classification.

Referring to FIG. 27, the dispensing pump 400 comprises an accumulatorcup 402 which is secured within the neck of a container 404 with athreaded closure 406. A nozzle head 408 is received on a piston stem 410which extends through the closure 406 and into the accumulator 402. Theloading cones 304, 306 of the present hyperboloid compression springassembly 300 are integrated into the opposing exterior surfaces of theclosure 406 and the top end of the piston stem 410 and the hyperboloidslotted tubular spring element 302 is snap received over and around thepiston stem 410 and upward cone extension 304 of the closure 406 so thatit engages the ramped loading cone walls 304, 306 of the piston stem 410and closure 406.

In operation, a forcible downward compression of the nozzle head 408causes a corresponding downward axial movement of the upper loading cone(piston stem head) 410/306 relative to the lower loading cone (closure)406/304 and outward deflection and loading of the spring element 302similar to the illustrations earlier described in FIGS. 9-12. Upon thesubsequent release of the nozzle head 408, the tubular spring element302 elastically contracts (radially inward) back to its normal at restshape and position, causing a forcible upward movement of the upperloading cone (piston stem) 410/306 and nozzle head 408 back to theirnormal at rest positions. The piston pump assembly 400 operates as knownin the art to draw material up from a dip tube connection 412 anddispense the material through the nozzle head 408.

It can therefore be seen that the exemplary embodiments provide uniqueand novel compression spring assemblies in which all the discretecomponents may be molded from a single plastic material to facilitatesingle stream plastic recycling. Further, the all plastic compressionspring assemblies can be advantageously used in all plastic dispensingpumps which can then also be easily recycled.

While there is shown and described herein certain specific structuresembodying various embodiments of the invention, it will be manifest tothose skilled in the art that various modifications and rearrangementsof the parts may be made without departing from the spirit and scope ofthe underlying inventive concept and that the same is not limited to theparticular forms herein shown and described except insofar as indicatedby the scope of the appended claims

What is claimed is:
 1. A compression spring assembly comprising: aslotted tubular spring element formed from a tensile polymer material;and first and second loading cones received at opposing first and secondends of said slotted tubular spring element, said loading cones beingaxially compressible toward each other within said slotted tubularspring element, whereby said slotted tubular spring element radiallyexpands in tension to create an opposing axial extension spring force.2. The compression spring assembly of claim 1 wherein said slottedtubular spring element is cylindrical.
 3. The compression springassembly of claim 1 wherein said slotted tubular spring element has auniform wall thickness.
 4. The compression spring assembly of claim 1wherein said slotted tubular spring element is hyperboloid in shape. 5.The compression spring assembly of claim 1 wherein said loading conesare symmetrical.
 6. The compression spring assembly of claim 1 whereinsaid loading cones have at least one wall section with a wall angle ofno less than 11 degrees.
 7. The compression spring assembly of claim 1wherein said loading cones have a first frustoconical pre-load sectionhaving a wall angle greater than 11 degrees and a second frustoconicalsection having a wall angle of no less than 11 degrees.
 8. Thecompression spring assembly of claim 1 wherein said loading cones have afirst frustoconical preloading section with a first wall angle and asecond loading section with a second wall angle which is less than saidfirst wall angle.
 9. A compression spring assembly comprising: a slottedtubular spring element formed from a tensile polymer material; and firstand second loading cones received at opposing first and second ends ofsaid slotted tubular spring element, said second loading cone beingaxially compressible toward said first loading cone within said slottedtubular spring element, whereby said slotted tubular spring elementradially expands in tension to create an opposing axial extension springforce.
 10. The compression spring assembly of claim 9 wherein saidslotted tubular spring element has strain reducing ribs extendinglongitudinally along opposing slot edges.
 11. The compression springassembly of claim 10 wherein said strain reducing ribs are symmetrical.12. A compression spring assembly comprising: a slotted tubular springelement formed from a tensile polymer material; and first and secondloading cones received at opposing first and second ends of said slottedtubular spring element, said second loading cone being axiallycompressible towards said first loading cone within said slotted tubularspring element, whereby said slotted tubular spring element radiallyexpands in tension to create an opposing axial extension spring force,and wherein said loading cones have a first frustoconical preloadingsection with a first wall angle and a second loading section with asecond wall angle which is less than said first wall angle.
 13. Thecompression spring assembly of claim 12 wherein said slotted tubularspring element is cylindrical.
 14. The compression spring assembly ofclaim 12 wherein said slotted tubular spring element has a uniform wallthickness.
 15. The compression spring assembly of claim 12 wherein saidslotted tubular spring element is hyperboloid in shape.
 16. Acompression spring assembly comprising: a slotted tubular spring elementformed from a tensile polymer material; and an upper movable loadingcone and a lower stationary loading cone received at opposing upper andlower ends of said slotted tubular spring element, said upper loadingcone being axially compressible toward said lower loading cone withinsaid slotted tubular spring element, whereby said slotted tubular springelement radially expands in tension to create an opposing axialextension spring force.
 17. The compression spring assembly of claim 1wherein said slotted tubular spring element has strain reducing ribsextending longitudinally along opposing slot edges.
 18. The compressionspring assembly of claim 17 wherein the strain reducing ribs aresymmetrical.
 19. The compression spring assembly of claim 17 wherein thestrain reducing ribs have parallel facing surfaces at the slot edges andopposed convex surfaces extending circumferentially outward from theslot edges.
 20. The compression spring assembly of claim 17 wherein thestrain reducing ribs have symmetrical convex surfaces extending radiallyoutward from the slot edges.